Adsorption enthalpies have been measured for polar molecules interacting with Wyodak coal. All of the polar adsorbates studied, including organic bases and 1-propanol, interact more strongly than predicted based on a model that includes van der Waals forces only. After the van der Waals component is subtracted from the total adsorption heat, the specific adsorption heat for each polar molecule on Wyodak coal is ∼1-4 kcal/mol more exothermic than its value on Illinois No. 6 coal. On alkylated Wyodak coal, the adsorption heats for organic bases are ∼1-3 kcal/mol as well. The adsorption heats for organic bases on alkylated Wyodak coal decrease in exothermicity by g5.0 kcal/mol, an amount that is similar to the specific hydrogen-bond interaction for each base with Illinois No. 6 coal. In contrast, 1-propanol's adsorption heat decreases by only ∼2 kcal/mol after alkylating the coal and 1-propanol's specific adsorption heat on alkylated Wyodak coal (6.8 kcal/mol) is the same as its specific adsorption heat on Illinois No. 6 coal. These results demonstrate that in addition to the van der Waals force, polar molecules experience two other forces on Wyodak coal, a ∼1-3 kcal/mol nonspecific dipole-induced dipole force and a g5.0 kcal/mol specific hydrogen-bond force. Organic bases lose their hydrogen-bond force but retain their nonspecific dipole-induced dipole force while 1-propanol loses its dipole-induced dipole force but retains its specific hydrogen-bond force after alkylating Wyodak coal. This interpretation of the data sugests that different modes exist on Wyodak coal for hydrogen bonding to 1-propanol than for hydrogen bonding to organic bases.